Office chair backrest



FIG. 1 is a front elevation view of the office chair backrest showing my new invention;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a right side elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a front perspective view thereof; and,

FIG. 8 is a rear perspective plan view thereof. 

CLAIM The ornamental design for an office chair backrest, as shown and described. 